tests/language_2/implicit_creation/implicit_new_or_const_test.dart

// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import "package:expect/expect.dart";

import "implicit_new_or_const_test.dart" as prefix;

// Test that const constructors with const arguments become const,
// and non-const constructors or const-constructors with non-const arguments
// do not (except in a const context, which is tested elsewhere).

main() {
  // Various valid object creation expressions.
  var x = 42; // non constant variable.

  var instances = <Object>[
    new C(x),
    new C(42),
    const C(42),
    C(x),
    C(42),
    new C.named(x),
    new C.named(42),
    const C.named(42),
    C.named(x),
    C.named(42),
    new prefix.C(x),
    new prefix.C(42),
    const prefix.C(42),
    prefix.C(x),
    prefix.C(42),
    new prefix.C.named(x),
    new prefix.C.named(42),
    const prefix.C.named(42),
    prefix.C.named(x),
    prefix.C.named(42),
  ];

  // Test that the correct ones are constant, and the rest are not.
  const c42 = const C(42); // Reference constant.

  for (var i = 0; i < instances.length; i++) {
    var c = instances[i];
    Expect.equals(c42, c);
    if (i % 5 == 2 || i % 5 == 4) {
      // The cases of C(42) without "new" are all constant.
      Expect.identical(c42, c, "$i");
    } else {
      // The rest are not.
      Expect.notIdentical(c42, c, "$i");
    }
  }
}

class C {
  final Object x;

  const C(this.x);
  const C.named(this.x);

  int get hashCode => x.hashCode;
  bool operator ==(Object other) => other is C && x == other.x;
}